thank you for your help, look, my objective is that:
This accounts should be synchronized ever, in the both servers should have the same user account, the same db, files, all, the same domain, for in the domain use the dns with this example:

ns1.domain.com -> (IP_OF_THE_FIRST_SERVER)
{if this server is down}-> the domain will use the second dns, and we will work normally, can you understand?
ns2.domain.com -> (IP_OF_THE_SECOND_SERVER)